With the development of the smart terminals and the development of wireless network technology, users expect to use the same terminal to access to the Internet at different locations. Different locations may be covered with different communication network; accordingly, terminal users may need to pay expensive roaming data service expenses for data transmission, especially in the case of international roaming.
To save expenses, the service expenses generated in international roaming shall be local. For this purpose, roaming business suppliers sign the agreement with the service providers in advance, to get the card information of the roaming countries, write the card information required by a plurality of roaming countries on the terminal in advance, And use the prewritten card information of the corresponding roaming countries directly to complete the business data localization when the terminal is roaming. However, for the card provided with mobile phone key identifier (Ki, Key identifier) is directly needed to get on the Internet, so the roaming business suppliers must sign an agreement with the global service providers and obtain the card information, but, actually, many service providers do not provide this service. Therefore, the supporting number of roaming countries is obviously limited. And, prefabricating a plurality of card resources causes a waste in the number of segment resources. Hence, it is expected that a method can conveniently provide service providers data transmission services in roaming countries to save roaming data service expenses.